Hummingbird Heartbeat (3:32)

Perry told BBC’s Newsbeat that her fiancé Russell Brand had an effect on Teenage Dream. Some of the tracks were recorded before the singer met the British comedian, but their relationship affected several of the later tracks. She said: “There are some songs on the album inspired by love. There’s a song called Hummingbird Heartbeat. He gives me that Hummingbird Heartbeat.”